But researchers have found that the overwhelming majority of people who commit mass public shootings are suicidal at the time of their attacks: They fully intend to die, either by a self-inflicted gunshot wound or a shootout with police.
Moreover, data on the outcomes of mass shootings bears this out. Nearly half of the perpetrators of mass shootings carried out between 1982 and 2018 took their own lives at or near the scene of their crime, according to a mass shooting database maintained by Mother Jones magazine. Add in the individuals who were shot and killed during subsequent encounters with police and about 7 in 10 mass shooters don't survive.
Certainty of death, in other words, is no deterrent to mass shooters. Most of them may, in fact, be driven by it.
“Because many offenders are suicidal and expect to be shot and killed, they wouldn't be deterred by places with armed guards or gun-toting citizens,” said criminologist Adam Lankford, who studies mass shootings at the University of Alabama. “In fact, a significant subset of these offenders have specifically targeted government buildings and military facilities” — places where armed opposition is all but certain.
In a 2015 study on mass murders, Lankford noted that “many mass murderers appear to care more about harming others than they do about protecting themselves.” Studying 185 public mass shootings between 1966 and 2010, he found reason to believe that “virtually all of those offenders may be suicidal or life indifferent.”
Other researchers have found that mass shooters who survive their crimes may not have intended to do so. “It is also important to emphasize that many who survived had planned to die but then changed their minds at the last minute,” Lankford said. “The Parkland school shooter, for example, had posted online that he planned to die during his attack, and apparently had a history of suicidal behavior and statements, despite his survival.”
For many mass shooters, provoking a lethal response by law enforcement officers is part of the plan. The phenomenon is so common that it has a name: “suicide by cop.” For certain mass shooters, suicide by cop “may appeal as a suitably masculine conclusion to their violent attacks,” Lankford writes.
Shooters intending to go out in a “blaze of glory,” either by their own hand or via a shootout with police, are unlikely to be deterred by the presence of more “good guys” with guns. The data on mass shootings would appear to bear this out.
Of the 97 mass public shootings that have occurred in the United States since 1982, 68 have ended with the shooter's death according to a database maintained by Mother Jones magazine. Of the 68 dead shooters, 47 killed themselves, 20 were shot and killed by police, and in one incident in 1982 an armed bystander killed a shooter as he fled the scene.
People intending to commit mass shootings often study previous mass shooters closely, attempting to emulate or surpass them. Most would-be mass shooters are well aware, in other words, that they're unlikely to survive.
Conversely, it's dubious that the presence of armed civilians would be much of a deterrent for the typical mass shooter. Researchers have found that many mass shooters exhibit a “pseudocommando” mind-set: an obsession with weapons and a “warrior” mentality. For those shooters, overcoming armed opposition may be an appealing and even central part of the fantasy.
“For some mass shooters, knowing they wouldn't be shot and killed could actually have a deterrent effect,” Lankford said. “There is no evidence, as far as I know, of a single mass shooter ever stating that he/she was selecting a target because it was a 'gun free zone.' ”
Factors like these are one reason serious gun violence researchers think that other policies are much better suited to reducing the toll of mass shooting deaths: universal background checks and bans on high-capacity magazines and assault weapons.